Improvement in tension mechanisms for sewing-machine shuttles



J. W. STRANGE.

Improvement in Tension Mechanisms for Sewing Machine Shuttles.

Patented June 20,1871;

wil-nesse's Inven ['0 r.

UNITED STATES PATENT QFFICE.

JOSEPH W. STRANGE, OF BANGOR, MAINE.

IMPROVEMENT IN TENSION MECHANISMS FOR SEWING-MACHINE SHUTTLES.

Specification forming part of Letters Patent No. 116,113, dated June 20,1871.

To all whom it may concern:

Be it known that I, J OSEPH W. STRANGE, of Bangor, in the county ofPenobscot and State of Maine, have invented a new and useful Improvementin Sewing-Machines; and I do hereby declare that the following, taken inconnection with the drawing which accompanies and forms part of thisspecification, is a description of my invention sufficient to enablethose skilled in the art to practice it.

This invention relates to a new and improved mode of adjusting theshuttle-tension, by which the adjustment is effected, either when themachine is in motion or when at rest, without removing the shuttle fromthe race; these results being effected by means of the deviceshereinafter described, or by their mechanical equivalents.

Figure 1 is a top or plan view. Fig. 2 is a side elevation of theshuttle, showing the bobbin in position. Fig. 3 is a cross-section takenon line 10 m, Fig. 2; and Fig. 4 is a similar section taken on line y a,Fig. 2.

Similar letters of reference indicate corresponding parts in the severalfigures.

In the drawing, A represents a section of the bed of a machine, and Bthe shuttle-race. a is the shuttle-carrier, which is connected by apitman to a crank upon shaft 1), upon which is secured the wheel D forexperimentally actuating the carrier. The shuttle c is arranged to beactuated by the carrier in the usual manner. d is a spring, one end ofwhich is secured to the inside of the shuttle near its rear end, asshown, and is so formed that its opposite end bears against the shell ofthe shuttle. e is a sliding block interposed between spring d and theshell of the shuttle, as is plainly shown in Fig. 3. A projection ofthis block extends through the shell in the slot m, as is shown in Figs.1 and 3, and it also extends to the edge of the shell, as is shown inFig. 3.

When the block e is moved toward the rear end of the shuttle as far asslot m extends, the spring d bears with nearly its full force againstthe side of the shuttle; but as the block is moved toward the pointed orfront end of the shuttle the pressure of the free end of the spring uponthe shuttle is diminished or taken off altogether as the slide is movedmore or less. The thread f leading from the bobbin g passes betweenspring 01 and the shell of the shuttle, as is shown in Fig. 4, thencethrough the hole 19 in the shuttle, near the free end of spring 01. Itwill be apparent that the pressure of the springupon the thread may begraduated by actuating the block 6, as before described; and as thepressure of the spring upon the thread constitutes the tension it may,

through the above-described means. If the machine be at rest and it isdesired to change the tension, the slide 0 is actuated without removingthe shuttle from the machine by-means of that part which moves in slotm, as shown in Fig. 1, any small instrument or the fingernail servingfor that purpose; but to adjust or change the degree of tension when themachine is in motion I employ the following devices: The plate 0 isarranged to slide in a suitable recess or groove, and is cut awaycentrally to allow a free movement of the shuttle and its carrier, asshown.

Two screws, marked h, pass through slots in plate 0 and enterscrew-holes in bed A, the slots being of such length as to allow asufficient end motion to the plate, which is imparted thereto by meansof thumb-screw k, which passes through screw-nut Z secured to bed A,while its inner end is secured in stud jupon plate 0 in such manner thatthe end motion of the screw in either direction, caused by its rotation,will be imparted to plate O. Two spurs or projections, marked 6 and i,respectively, are formed upon or secured to plate 0 so as to bearagainst or slide close to the vertical side of the shuttle-race, asshown, while two small holes, marked at and 0, respectively, are formedin the shell of the shuttle, as is plainly shown in Figs. 1 and 2, sothat when the shuttle is actuated these spurs will enter the holes inthe shuttle.

If it be desired to increase the tension, plate 0 should be moved to theright, as viewed in Fig. 1, when the forward movement of the shuttlewould bring block 0 in contact with spur 47, thereby forcing the blocktoward the rear end of the shuttle and away from the free end of thespring d, thereby allowing the spring to act with greater force upon thethread, and increasing its tension, as before described,

while if a decrease of tension is required it is therefore, be adjustedwith great delicacy I only necessary to move plate 0 to the left by themeans described, when spur '2', entering through hole 0, would force theblock toward the free end of the spring, thereby decreasing the pressureupon the thread and the consequent tension.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-- 1. In combination with shuttle c, thespring d and block 0, when all are constructed and arranged to operatesubstantially in manner as and for the purposes specified.

2. The sliding bar 0 with its spurs i and i, when constructed andarranged to operate substantially as and for the purposes specified.

JOSEPH W. STRANGE.

Witnesses:

H. L. MITCHELL, H. B. FARNHAM.

